$xsmall-break:768px;
@mixin xsmall(){
  @media screen and (max-width: $xsmall-break) {
    @content;
  }
}
@mixin minxsmall(){
  @media screen and (min-width: 320px) and (max-width: $xsmall-break) {
    @content;
  }
}
@mixin minsmall414(){
  @media screen and (max-width: 414px) {
    @content;
  }
}
@mixin small(){
  @media screen and (min-width: $xsmall-break) {
    @content;
  }
}
@mixin smallh800(){
  @media screen and (max-height: 800px) {
    @content;
  }
}
@mixin lgallh1280(){
    @media screen and (max-height: 1280px) {
        @content;
    }
}
// ip4
@mixin max320(){
   @media screen and (max-width: 320px) {
    @content;
   }
}
// ip6
@mixin max375(){
   @media screen and (min-width: 321px)  and (max-width: 375px){
    @content;
   }
}
// ip6plus
@mixin max414(){
   @media screen and (min-width: 376px) and (max-width: 414px){
    @content;
   }
}
// ipad
@mixin max768(){
   @media screen and (min-width: 415px) and (max-width: 768px){
    @content;
   }
}
//大于ipad
@mixin min768(){
   @media screen and (min-width: 769px){
    @content;
   }
}